Dynamic balancing method and apparatus

ABSTRACT

Method of removing imbalance from a rotating body. A plurality of weights movable in a first race are maintained in a first position relative to the race at a first predetermined rotation speed. The weights are maintained in said position until a second predetermined rotation speed is reached at which time the weights are released.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of prior U.S. patent application Ser. No.08/419,641 filed Apr. 10, 1995 which, in turn, is a continuation-in-partof U.S. patent application Ser. No. 08/246,864 filed May 20, 1994,which, in turn, is a continuation-in-part of U.S. patent applicationSer. No. 08/066,307 filed May 21, 1993, now U.S. Pat. No. 5,60,017which, in turn, is a continuation-in-part of U.S. patent applicationSer. No. 07/887,340 filed May 21, 1992, now abandoned in favour ofpending continuation U.S. patent application Ser. No. 08/175,320 filedDec. 29, 1993.

INTRODUCTION

This invention relates to a balancing method and apparatus and, moreparticularly, to a balancing method and apparatus used for dynamicallybalancing an out of balance condition in a rotating body.

BACKGROUND OF THE INVENTION

Many different apparatuses for balancing an out of balance condition ina rotating body are known. Such apparatuses generally include acounterweight having a weight of a predetermined value which is locatedat a predetermined position from the axis of rotation to oppose animbalance in the rotating body. The magnitude of the imbalance isgenerally known and, accordingly, the necessary weight and position ofthe counterweight can be calculated so that the weight is positionedwhere it will act to counter the known imbalance. These apparatusesfunction satisfactorily for most purposes under which they are employedbut are not precise or useful enough for other applications.

Under dynamic conditions; that is, when a body is rotating about an axisand an imbalance in the rotating body develops because of externalconditions or otherwise, the prior art is much less satisfactorilydeveloped. For example, in a drill bit or in a drillstring, vibrationinduced forces during operation can create severe imbalances. Onetechnique used to counteract such imbalances is disclosed in U.S. Pat.No. 4,905,776 (Beynet et al). Beynet et al teach a vibration dampeningassembly with a plurality of annular grooves or races located about theperiphery of the assembly and extending axially therealong. A pluralityof balls or rollers are located in each of the races. Such balls orrollers are free to move along the races and thereby counteract theimbalance forces.

A further similar structure is disclosed in U.S. Pat. No. 4,674,356(Kilgore). Kilgore teaches a plurality of balls freely movable in a raceformed in an outer circumferential surface of the body which balls areused to counterbalance an imbalance in the rotating member.

There are, however, disadvantages in such prior art. Although the Beynetet al reference is satisfactory to remove large imbalances from therotating body, it is difficult to utilise the teachings of Beynet et alwhere the length of the balancing apparatus is necessarily restrictedwhich is often the case. Likewise, while the teachings of Beynet et alare satisfactory to generally remove large imbalances from thedrillstring, there is no provision therein for removing all or most ofthe remaining imbalance thereafter, particularly the imbalance that mayremain when the balls in the races of Beynet et al are located at theiroptimum positions in the races to counteract the imbalance.

This latter problem is also inherent in the above mentioned Kilgorereference. Kilgore teaches two counterbalance structures, one located ateach end of a shaft, to offset the imbalance in the shaft or theimbalanced forces in the rotating structure which is movable with theshaft. If the balls are not located at their optimum positions, theimbalance in the shaft will not be removed.

The dynamics of weight movement in the various races of the balancingapparatus is an important consideration for efficient movement of theweights in order for the weights to properly "set up" and removeimbalances under various operating conditions. Such conditions mayinclude the acceleration of a rotating apparatus from zero to somepredetermined steady-state operating speed or revolutions (r.p.m.'s),the operation of a machine between two natural modes of vibration whichare inherent in a particular system and the operation of a machine orapparatus that is subjected to additional non-one time per revolutionexcitations; that is, forces which are applied to the apparatus withfrequencies different from the rotational speed of the apparatus.

In a single race with movable weights, many of the weights in the racetend to respond to the varying operating conditions in a similar generalfashion in view of the similar masses and sizes of the movable weights.In addition, the weights will often contact each other and interferencewith the independent movement of the individual weights results. Thiscan lead to a case wherein an imbalance condition is not removed orsubstantially removed. However, with more than one race, each racehaving a plurality of weights, the movement of the weights in each raceis independent from the weights of the other race and, accordingly, eachplurality of weights responds to varying operating conditions in adifferent manner. This is beneficial because if the movable weights inthe first race respond inappropriately to remove an imbalance, such asdrifting away from their optimal desired position, the movable weightsin the second race may respond appropriately and may also tend toinfluence, compensate for, or terminate the inappropriate behaviour ofthe movable weights in the first race. These phenomena in two race andgreater apparatuses are referred to as "race for race" compensation.

The independent movement of the weights at different times is under theinfluence of several variables. Some such variables include the materialof the weights and races, the configuration of the weights and races,the size of the weights and races, the diameter of the various races andthe presence or absence of fluids in the various races. If there arefluids present, then the viscosities of the fluids used are ofparticular importance.

The independence of the movement of movable masses can be established byvarying the dynamics of the individual races. The dynamics of the weightor ball movement in a manner different than having balls of differentsizes in different grooves is of importance. It has been found that,with other factors being equal, balls made from a denser material willrespond faster to imbalance than lighter balls. This faster response ofthe weights or balls may be implemented by manufacturing the movableweights from a material such as carbide material, which is denser thanthe density of known steel material. It is also noted that earliermovement of the balls can result if the weights are made of hardmaterial and are therefore able to move more freely. Likewise, it isnoted that earlier movement of the weights or balls can be achieved ifthe races in which the weights move are of a relatively hard material.

A further parameter affecting the movement of the weights within theraces is the presence or absence of fluid and the viscosity of suchfluid. More particularly and with other factors being equal, the use ofa fluid with a greater viscosity will delay the movement of the balls orweights in the race while the presence of a fluid having a lesserviscosity will allow the movement of the weights to take place morereadily. Thus, if there are a plurality of races, the use of differentfluids in different races will allow the movement of the weights in eachrace to take place at a predetermined rate which may be useful incertain applications.

For example and, again, other factors being equal, if there are tworaces with the same size weights in each race, the use of a fluid with afirst viscosity in the first race and a fluid with a second viscosity ina second race, the viscosities of the two fluids being different, theweights in the second race with the fluid of the second race having ahigher viscosity will, upon startup, move and "set-up" earlier to removethe imbalance than the balls or weights in the first race. Conversely,the higher viscosity fluid will tend to delay the movement of theweights or balls at operating speeds when the balls are already "set-up"to remove an initial imbalance and a further imbalance appears in theapparatus. Thus, depending on the operating characteristics desired, afluid of a first viscosity can be used to enhance "set-up" at low speedsand a fluid of a second viscosity can be used to enhance "set-up" athigher speeds. In this manner, it is possible to design a system whichwill set up to remove the imbalance at a predetermined time,predetermined speed of angular rotation, or predetermined angularacceleration of the member. And, while a system using two races has beendescribed, it is contemplated than different fluids could be used ineach race of a balancing apparatus, wherein the apparatus has three ormore races.

It is again emphasized that the explanations given herein are believedto be correct based on empirical and calculated results and laboratorysimulations. However, subsequent investigations may well reveal thatthese explanations will be modified and such explanations are given herefor the purpose of full disclosure of the technology which is sought tobe protected.

SUMMARY OF THE INVENTION

According to one aspect of the invention, there is provided a balancingapparatus to remove imbalance in a rotating body comprising a firstplurality of weights movable within a first circular race, a secondplurality of weights movable within a second circular race, said firstcircular race further including a first fluid with a first viscosity,said second circular race further including a second fluid with a secondviscosity, said viscosity of said second fluid being different from saidviscosity of said first fluid.

According to a further aspect of the invention, there is provided abalancing apparatus comprising a first circular race rotatable about afirst axis, a first plurality of weights movable within said first race,a locking member operable to maintain said first plurality of weights ina first position reached at a first predetermined angular velocity andto release said first plurality of weights from said first position at asecond predetermined angular velocity.

According to yet a further aspect of the invention there is provided amethod of removing the imbalance from a rotating apparatus comprisingincreasing the rotation speed of said apparatus until a firstpredetermined rotation speed is reached, maintaining a plurality ofmovable weights in a first race in a first position of said weightswhich is reached at a first predetermined rotation speed, increasingsaid rotation speed of said apparatus to a second predetermined rotationspeed and releasing said plurality of movable weights from saidmaintained position at said second predetermined rotation speed.

According to yet a further aspect of the invention, there is provided abalancing apparatus to removed imbalance in a rotating body comprising afirst plurality of weights in a first race, said first race having afirst configuration and a second plurality of weights in a second race,said second race having a second configuration, said configuration ofsaid first race being different from said configuration of said secondrace.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Specific embodiments of the invention will now be described, by way ofexample only, with the use of drawings in which:

FIG. 1 is a side sectional diagrammatic view of a first embodiment ofthe counterbalancing apparatus according to the invention;

FIG. 2 is an end view taken along II--II of FIG. 1;

FIG. 3 is a side sectional diagrammatic view of a second embodiment ofthe counterbalancing apparatus according to the invention;

FIG. 4 is an end view taken along IV--IV of FIG. 3;

FIG. 5 is side sectional view of a further embodiment of thecounterbalancing apparatus according to the invention;

FIG. 6 is a side sectional diagrammatic view of a further embodiment ofthe counterbalancing apparatus according to the invention;

FIG. 7 is a side sectional diagrammatic view of the apparatus of FIG. 6illustrated in its operating position;

FIGS. 8A and 8B are end views of a further embodiment of the inventionmounted about a shaft and illustrating the counterbalancing apparatus inassembled and disassembled condition about the shaft, respectively;

FIG. 9 is a diagrammatic side view of yet a further embodiment, thecounterbalancing apparatus according to the invention being operablylocated within a shaft;

FIG. 10 is a diagrammatic end view taken along X--X of FIG. 9illustrating a representative position of the movable weights duringrotation of the shaft in which the apparatus is located; and

FIG. 11 is a view of the counterbalancing apparatus according to theinvention illustrating the vertical radial from the axis of theapparatus.

FIG. 12 is a diagrammatic cross-sectional view of a ball retainingapparatus according to a further embodiment of the invention;

FIG. 13 is a diagrammatic cross-sectional view of a ball retaining pinapparatus according to a further embodiment of the invention;

FIG. 14 is a cross-sectional view of two versions of balancing devicesaccording to the invention, either of which might be used with anordinary ball bearings;

FIG. 15A is a diagrammatic view of the outside of the tub of a washingmachine with balancing devices mounted thereon;

FIG. 15B is a diagrammatic view taken along 15B--15B of FIG. 15A;

FIG. 15C is a diagrammatic view taken along 15C--15C of FIG. 15A;

FIG. 16 is a diagrammatic view of the rear end drive axle anddifferential of a vehicle;

FIG. 17 is a view of a typical crankshaft which is connected to a pistonof a compressor or internal combustion engine with balancing devicesattached according to the invention;

FIG. 18 is a side-sectional diagrammatic view of yet a furtherembodiment of the invention;

FIGS. 19A and 19B illustrate a circumferential I-beam arrangementaccording to a further aspect of the invention; and

FIG. 20 illustrates a mounting arrangement according to a further aspectof the invention.

FIG. 21 is a diagrammatic isometric view of a weight locking apparatusaccording to a further aspect of the invention which is used to restrainthe weights over a predetermined range of speeds;

FIG. 22 is a side, diagrammatic cutaway view of a balancing deviceaccording to the invention in which the movable weights are first heldin position until a predetermined speed of rotation is reached whereuponrelease then occurs;

FIG. 23 is a diagrammatic cutaway view of a balancing device accordingto the invention which utilizes a plurality of free weights and afurther set of weights released by control weights; and

FIG. 24 is a diagrammatic cutaway view of two representative raceconfigurations which will modify the behaviour of the weights duringoperation according to a further aspect of the invention.

DESCRIPTION OF SPECIFIC EMBODIMENT

Referring now to the drawings, a counterbalancing apparatus according tothe invention is illustrated generally at 10 in FIG. 3. It comprises afirst set of annular races or grooves 11, 12, 13, 14, 15, it beingunderstood that oppositely located races 11, 15 are convenientlyidentical and that oppositely located races 12, 14 are also convenientlyidentical. It will be understood that the term "race" or "races" refersto the physical boundary within which the weights move during operationor, alternatively, it could also include a pathway which acts to guideweights movable thereon or therein as described in greater detail below.

A plurality of weights 21, 22, 23, 24, 25, conveniently spherical in theform of balls, are mounted in the races 11, 12, 13, 14, 15,respectively. The plurality of weights in each of the races areconveniently all the same size and weight; that is, the weights 21 inrace 11 are all the same size and weight, the weights 22 in race 12 areall the same size and weight and so on. It is important, however, thatthe weights in at least two of the races be different in size andweight; that is, the weights 23 in race 13 are preferably larger andheavier than the weights 24 in race 14. It will be further understoodthat the term "weights" may include a variety of different shapes suchas spherical, disc or cylindrically shaped weights which are movablewithin the races or guided thereby. The term may also include weights ofdifferent configuration as is described further in this specification.

The balls 21, 22, 23, 24, 25 are freely movable in their respectiveraces 11, 12, 13, 14, 15 about the circumference of the counterbalancingapparatus 10. An appropriate lubricant 30, conveniently silicon, isadded to the counterbalancing apparatus 10 in order to reduce thefriction between the balls and their respective races or grooves, toalso reduce the noise made by the balls when the counterbalancingapparatus is in operation, and to create an appropriate amount ofviscous dampening to the balls as will be described hereafter.

The balls 21, 22, 23, 24, 25 may be manufactured from a hardenedmaterial. Likewise, the races or grooves 11, 12, 13, 14, 15 may behardened. The hardening is desirable in order to prevent the formationof "flats" on the balls or races which tend to reduce the ability of theballs to move freely within the grooves or races and thereby retard theeffectiveness of the counterbalancing movement of the balls.

OPERATION

In operation, the counterbalancing apparatus 10 is installed on shaft 32so as to fixedly rotate therewith such as by using a key 31 between theapparatus 10 and the shaft 32. The operation of an imbalanced membergenerally illustrated at 33, which creates an out of balance condition,is initiated and shaft 32 rotates with member 33 and counterbalancingapparatus 10 as illustrated.

As an out of balance condition originates within member 33, the balls21, 22, 23, 24, 25 in each of the races 11, 12, 13, 14, 15 move and actto counterbalance the out of balance condition.

It is difficult to precisely state all the principles by which the ballsare known to move and while it is believed that empirical data willsubsequently lead to formulae and better understanding to predict theoptimal behaviour of the counterbalancing apparatus 10, the followingexplanation is given with the expectation that further informationpresently not known will amplify, modify or change such explanation.

It is believed that the larger balls 23 in race 13 will remove thelarger out of balance condition in member 33. The somewhat smaller balls22, 24 in races 12, 14 will act to remove the somewhat smaller out ofbalance condition in member 33. Finally, the smallest balls 21, 25 inraces 11, 15 will act to remove the smallest out of balance condition inmember 33. Thus, the entire out of balance condition in member 33 isremoved by "fine tuning"; that is, by removing the imbalance underdynamic conditions with a plurality of different sized balls positionedin separate races which balls optimally remove different degrees ofimbalance.

With reference to FIG. 4 which illustrates the leftmost race 11 of FIG.3 with the balls 21 in a representative and dynamic balanced positionoffsetting the imbalance in member 33, as viewed with a timing lightadjusted for appropriate shaft r.p.m., it has been found that theoptimum behaviour for the balls 21 occurs when they do not contact eachother in the dynamically balanced position as is illustrated. It hasbeen found that when many of the balls 21 come into contact with eachother, the balancing phenomenon is not optimal and modification of thecounterbalancing apparatus 10 may be necessary by way of structural orweight changes.

The embodiment of the invention illustrated in FIGS. 3 and 4 isconveniently used when there is a large potential imbalance problem inmember 33 under dynamic operating conditions. If the potential imbalanceproblem in member 33 is small, the number of races and associated ballstherein can be reduced to as few as two (2), with all of the balls ineach respective race being the same size and weight and the balls of thefirst race being different in size and weight from the balls of thesecond race, the former balls being larger and acting to remove thelarge imbalance and the latter balls being smaller and acting to removethe smaller remaining imbalance.

Referring now to FIGS. 1 and 2, there is illustrated a furtherembodiment which is desirably used when the width "W" as illustrated inFIG. 1 is limited. In this embodiment, there are three grooves or races34, 35, 36 with balls 40, 41, 42 mounted therein, respectively. Theballs 40 in race 34 are all the same size and weight. The balls 41 inrace 35 are likewise all the same size and weight and the balls 42 inrace 36 are likewise all the same size and weight. The balls 40 in race34, however, are larger and heavier than the balls 41 in race 35 which,in turn, are larger and heavier than the balls 42 in race 36. Underoperating conditions and when an imbalance occurs in member 33 duringrotation of shaft 32, the balls 40, 41, 42 will assume positions whichcounter the imbalance. A representative view of the positions of balls40, 41, 42 illustrated in FIG. 2 would be positions where the imbalanceis removed optimally; that is, and as earlier described, the balls ineach race or groove do not contact each other.

A further embodiment of the invention is illustrated in FIG. 5. In thisembodiment, wherein the width "W" is again of concern, a first pluralityof cylindrical disc-like weights 50, 51, 52 are positioned to be freelymovable in each of the races 43, 44, 45 which races 43, 44, 45 areformed by circumferential dividers 53, 54, 55 which are positioned overhub 60 and between spacers 61, 62, 63. A silicon lubricant 65 is addedto the interior of the housing 64 and a closure member 70 is connectedto the housing 64 by the use of cap screws 71.

In operation, the housing 64 is fixedly mounted on the rotating shaft 32as described in association with the method of FIG. 1. As an imbalancearises in member 33, the cylindrical weights 50, 51, 52 will freely movewithin the races 43, 44, 45 until they assume a position wherein theycounterbalance the imbalance occurring in the member 33. It has beenfound that it is preferable to give the sides of the cylindrical disks50, 51, 52 a slight bow in order that the discs 50, 51, 52 contact thedividers 53, 54, 55 with a minimal surface area wherein they are notinfluenced by any possible suction which might otherwise occur betweenthe dividers 53, 54, 55, the silicon lubricant 65 used and the discs 50,51, 52 of the FIG. 5 embodiment. It is preferable that the cylinders ordiscs 50, 51, 52 move as freely as possible within the races 43, 44, 45between the dividers 53, 54, 55 as is likewise true for the weights andballs of the FIGS. 1 and 3 embodiments.

Yet a further embodiment of the invention is illustrated in FIGS. 6 and7, FIG. 6 illustrating four (4) grooves or races and FIG. 7 illustratingonly three (3) grooves or races. In this embodiment, thecounterbalancing apparatus generally illustrated at 75 is symmetricalabout both axes 76, 72 and is mounted to a shaft 32 similar to the FIG.1 embodiment.

In this embodiment, however, a central circumferential member 73 madefrom a solid piece of material is machined with a plurality of annularraces generally illustrated at 77 on both faces. Balls are mounted inthe races 80, 81, 82, 83, the balls mounted in the outermost race 80being the largest and the balls in the innermost race 83 being thesmallest. After providing the silicon lubricant within each of the races77, two end plates 85 are mounted to the central circumferential member73 by the use of cap screws 82. The operation is similar to theoperation of the FIG. 3 embodiment; that is, when an imbalance occurs inmember 33, the balls in each race will assume a position wherein theimbalance is removed.

It is not again presently known why such is the case, but it has beenfound that seven (7) balls or weights in each race or annular space ofeach of the embodiments appear to be an optimal number. It is, however,also believed that a greater or smaller number of balls or weights wouldusefully serve to remove various imbalances under various operatingconditions.

A further embodiment of the invention is illustrated in FIGS. 8A and 8B.In this embodiment, the counterbalancing apparatus 78 according to theinvention is illustrated as being made from two sections 90, 91, whichsections are mounted about shaft 32 by cap screws 92, 93 and whichsections 90, 91 are freely removed from shaft 32 by removing the capscrews 92, 93. This embodiment is particularly useful where minimalmodifications are desirably made to the rotating shaft 32 or to the outof balance member 33 (FIG. 1). Rather, the counterbalancing apparatus 78is simply connected to the shaft 32 at a position where it is possibleso to attach the counterbalancing apparatus 78 and the cap screws 92, 93are tightened to firmly couple the apparatus 78 to the shaft 32.

Yet a further embodiment is illustrated in FIGS. 9 and 10. In thisembodiment, it is contemplated that the counterbalancing apparatus 87 ismounted inside the outer circumference of a rotating shaft 32. Asillustrated in FIG. 9, the grooves or races 100, 101, 102 are machineddirectly into the solid material of shaft 32 and the balls 103, 104, 105are positioned directly therein for free movement relative thereto. Acover 110 is connected to the shaft 32 and the balls 103, 104, 105 arethereby retained. In operation, as an out of balance condition occurseither in the out of balance member 33 (FIG. 1) or in shaft 32 itself,the balls 103, 104, 105 will orient themselves in a configuration suchas the configuration illustrated in FIG. 10. In such positions, theshaft 32 and/or the imbalanced member 33 is balanced by the position ofthe balls 103, 104, 105 under dynamic operation conditions.

It has been found that under certain conditions and particularly atlower r.p.m.'s of the counterbalancing apparatus 10, the weights 21(FIG. 11) will tend to remain in a substantially stationary position inthe race 11 until the revolutions per minute of the counterbalancingapparatus increase to the point where the weight 21 is carried aroundthe outermost point of the inside diameter of the race 11 or from oneside of the radial 25 to the other or until the centrifugal force actingon the weights forces them outwardly until they are in an operatingengagement with the outer surface of the race 11 which will then exert acertain friction force that will tend to carry them around with the race11. After operating speed occurs, the weights 21 will then quicklyrearrange themselves with minimal movement so as to properly balance anyimbalance condition. It has been found, for example, that at higherrotational speeds of the balancing device, the weights 21 within theraces will quickly rearrange themselves to set off any imbalance in thedevice. However, at lower speeds, this not always the case and,accordingly, it is convenient to utilise means to move the weights withthe race or, at least, to provide a force on the movable weights whichwill tend to move the weight with the race as it rotates about its axis.

Any delay in removing the imbalance is not advantageous since if ashaft, for example, being in balance and rotating, suddenly encountersan out-of-balance condition, it is conceivable that the weights 21 maynot move quickly enough to remove the out-of-balance condition beforedamage results to the system.

The means used to improve the "quickness" with which the system respondsto remove the out-of-balance condition can take several forms. It is,for example, contemplated that a substance could be added to the races11 so that a force is imparted to the weights 21 which force will besuch that the weights 21 will move from a stationary position asindicated to a position "over-the-top" of the member 10 and from oneside of the radial 25 extending from the axis 26 of the member 10 to theopposite side. Alternatively, mechanical or electrical means could beused.

With reference to FIG. 11, it is contemplated that the initial movementof the weights 21 within the race 11 may occur by the addition of asubstance to the races 11 that will initially give a degree of force tothe weight so that the movement of the weights 21 is initiated by thesubstance. For example, such a substance could be a fluid of aconsistency to impart the rotational movement to the weights, such asgrease. An exhaustive list of all such substances is not immediatelycontemplated but such a list might include virtually any substance toinitiate movement of the weights 21. Even sand is contemplated as such asubstance but, of course, sand may be inappropriate because ofcontamination and eventual binding of the weights 21 within the race 11which would affect normal operation where quickness of weight movementmay not be necessary.

It is also contemplated that the initial weight movement could beinitiated externally of the counterbalancing apparatus 10. For example,if the weights 21 were made of a magnetic material, an external probe(not illustrated) could apply a suitable magnetic field to the weights21 which would allow the weights 21 to immediately commence movement inthe event an imbalanced condition is encountered. This would be intendedto reduce the rotation time of the weights 21 so that the imbalancedcondition can be removed and would thereby reduce the chance of damageto the out-of-balance apparatus.

Reference is made to FIG. 12 which illustrates the balancing devicegenerally illustrated at 106. A liquid 107 is added to the balancingdevice 106 and takes a level 108 above the movable weight in the form ofball 103. A V-shaped race 109 is formed in race 110 in which ball 103 isintended to move. The V-shaped race 109 has a plurality of passages 111which extend from the race 109 to a liquid reservoir (not illustrated).

In operation and when the balancing device 106 begins to rotate, theliquid 107 will tend to rotate with the race 110 and, therefore, willexert a force on ball 103 which tend to rotate the ball 103 with therace 110. As the speed of rotation of the balancing device increases,the centrifugal force on the liquid will increase and, therefore, therewill be a tendency for the liquid 107 to exit through passageway 111 andthereby to terminate any further influence over the movement of ball 103which, by that time, will be rotating at the same speed as the balancingdevice 106. This is beneficial for the previously mentioned reasons,namely that if the balls 103 move quickly at speed, any imbalancearising will be quickly corrected.

A further embodiment of the invention is made with reference to FIG. 13.The balancing device generally illustrated at 200 includes a movableweight in the form of a ball 201 and includes a pin 202 which is springmounted within a radially outwardly extending opening 204. A compressionspring 203 acts on the pin 202 to force it inwardly to the positionindicated and thereby restrains movement of the ball 201 upon initialrotation of the balancing device about axis 206.

As the balancing device 200 commences to rotate about axis 206, the pin202, in the position illustrated, will cause the ball 201 to rotate withthe race 205. The speed will increase and as it does so, the centrifugalforce acting on the pin 202 will tend to move the pin 202 outwardly fromaxis 206 in opening 204 thereby allowing the ball 201 to move in therace 205 thereby to freely assume any position to correct an imbalancein the rotating machinery to which the balancing device 200 is attached.

Reference is now made to FIG. 14 which diagrammatically illustrates twoembodiments of the invention which may be used with a bearing 300 havingstandard balls 301 mounted so as to allow rotation of shaft 302 withreduced friction. However, it is desirable to remove imbalances in theshaft 302 and, to that end, a balancing device 303 or a balancing device304 may be added.

Balancing device 303 is connected so that it rotates with the shaft 302and the movable weights in the form of balls 305, 307, 308 move aboutaxis 306 of shaft 302 in races which are positioned concentrically andoutwardly in a plane transverse to the direction of axis 306 and, inbalancing device 304, the weights in the form of balls 310, 311, 312rotate in races which are longitudinally spaced and coaxial to shaft 32.

The balls 305, 307, 308 are of different diameters and this applieslikewise to the diameter of balls 310, 311, 312. Either configurationmay be useful depending upon the geometrical considerations present inthe system which is being used which includes shaft 302 and bearing 300.

Reference is now made to FIG. 15A which illustrates the clothescontaining cylinder or "spin basket" 400 of an ordinary washing machinerotatable about the axis of rotation 406. Two balancing devices 402, 403are connected to the basket 400 to remove any imbalance upon operationalthough one, of course, may be sufficient to remove imbalances. Thebalancing devices 402, 403 may again take two different forms.

Referring initially to FIG. 15B, the balancing device 402 may take theform of a plurality of races 404, 405 which extend circumferentiallyabout axis 406 and are coaxial with axis 406. Movable weights in theform of balls 407, 408 are mounted in the races 404, 405 and serve toremove imbalances when the tub 400 is rotated.

Alternatively, the balancing device 402 may have races 409, 410 machinedin a plane transverse to axis 406. The balls 411, 412 are movable intheir respective races 409, 410 and, again, remove imbalances when thebasket 400 rotates about axis 406.

Yet a further embodiment of the invention is illustrated in FIG. 16 inwhich the rear end of a vehicle 500 is diagrammatically shown. A gearbox or differential 501 has two axles 502, 503 extending outwardly fromthe gearbox 501 and connect to wheels 504, 505 which, of course, rotatewith axles 502, 503 when the vehicle is under operation.

An imbalance may arise in the system. For example, the tires 504, 505may become out of balance for various reasons including the fact thatflats form on the tires. This is particularly true in formula race carswhere the speeds of the cars vary greatly throughout a circuit and thetires are subjected to highly variable forces.

To correct the imbalance, balancing devices 506, 507, 508, 509 may beadded to axles 502, 503, respectively, although only one per axle may berequired. These would function in the same way as has been discussed asthe axles 502, 503 rotate both axially and about gearbox 501 as isillustrated. In the event the rotation about gearbox 501 is not severe,it may be convenient to mount the balancing devices 508, 509 on thewheels 504, 505 rather than on the axles 502, 503 as is shown in FIG.16.

Reference is now made to FIG. 17 which illustrates a crankshaft 600having a crankpin 605 to which is attached piston rod 601 which isconnected to piston 602. Piston 602 may be used, for example, in acompressor. Two balancing devices 603, 604 are connected to crankshaft600 as illustrated. The operation of each is similar to the operationsdescribed and they serve to continuously remove imbalances in the systemas previously set forth.

Reference is now made to FIG. 18 wherein six circumferential andconcentric races are illustrated in the balancing device 700. In thethree (3) outer races 701, 702, 703, the weights 704 are of identicaldiameters. In the inner races 710, 711, 712, the balls 713 in race 710are of identical size while balls 714 in race 711 are of identical sizeand balls 715 in race 712 are of identical size, the sizes of the balls713, 714 and 715 decreasing as the axis 716 is approached.

Reference is now made to FIGS. 19A and 19B wherein a further embodimentof the invention is illustrated which utilizes a circumferential I-beamand movable weight combination generally illustrated at 800. The I-beam801 is mounted around the circumference of member 802 which rotatesabout axis 803 by welding or by attachment, for example, and a pluralityof movable weights 804 are mounted on the I-beam 801 so as to be movablerelative thereto. This embodiment of the invention has the advantagethat it is inexpensive to manufacture and may be convenient in someapplications such as where friction between the weights 804 and theI-beam 801 is not a large problem such as where the apparatus 800 issubmerged in a liquid.

Reference is now made to FIG. 20 which illustrates an apparatusgenerally shown at 900 having a plurality of races 901 with movableweights 902 therein mounted about a member at increasing distances fromthe axis of rotation 903. While the weights 902 are shown as increasingin size as the distance of the weights 902 from the axis 903 increases,it will be understood that the sizes may remain constant or, indeed, thesize may decrease as distance from the axis 903 increases.

Yet a further embodiment of the invention is illustrated in FIG. 21. Inthis embodiment, a plurality of weights or balls generally illustratedat 1000 is illustrated in a race 1001 in which, ordinarily, the weights1000 are free to move. A circular disc 1002 is mounted about theperiphery of the balancing apparatus generally illustrated at 1003 andthis disc 1002 is axially movable as indicated by the arrows by theinfluence of a two way solenoid 1004. The disc 102 is operably connectedto plate 1010 by pins 1011 located about its periphery.

The solenoid 1004 is connected to a tachometer (not shown) whichmeasures the RPM count of the balancing apparatus 1003. When thetachometer reading reaches a certain and predetermined value, itinitiates movement of the plate 1010 by activating solenoid 1004. Whenthe solenoid 1004 moves leftwardly as viewed in FIG. 1, it will lock theweights or balls 1000 in position. Thereafter, when the tachometerreaches a second value, it will move the solenoid 1004 rightwardly whichwill move plate 1002 away from and release the balls or weights 1000.Such a configuration can be useful when it is desired to remove animbalance over a certain speed range and, thereafter, to lock the balls1000 in place after they assume a final balancing position to remove anyimbalance which exists when the weights 1000 have been released.

Reference is now made to FIG. 22. In this embodiment, the weights orballs 1100 are held or "locked" in position by the force exerted betweenthe balls 1100 and a material 1101, conveniently rubber, which ispositioned within the groove 1103. One side of the rubber ball retainingmaterial 1101 is mounted in a movable half-groove collar 1110. Collar1110 has a plurality of spring mounted pins 1111 which tend to bias thecollar 1110 into contact with control balls 1112 mounted intermittentlyabout the circumference of the balancing apparatus 1113. Each of thecontrol balls 1112 are biased to move inwardly by springs 1114.

In operation, when the balancing apparatus 1113 commences rotation, thebalancing weights 1100 are securely held in position by the collar 1110and the face plate 1120 until a predetermined rotation speed is reached.Thereafter, centrifugal force tending to move control balls 1112outwardly against the force of springs 1114, will allow the balls 1112to move outwardly relative to the axis of rotation 1121 until thecollars 1110 are not restrained by being in contact with balls 1112.Collars 1110 will move towards each other thereby releasing thebalancing balls 1100 and allowing them to move freely into a positionwherein any imbalance is substantially reduced or removed. When theapparatus subsequently is lowered in rotation speed, balls 1112 will beforced inwardly by springs 1114, the collars 1110 will move outwardly toretain the balancing balls 1100 which will subsequently be held inposition until the predetermined angular rotation speed is againsubstantially reached.

Reference is now made to FIG. 23 in which the balancing apparatus isgenerally illustrated at 1200 which rotates about axis 1201. Apparatus1200 has three grooves or races 1202, 1203, 1204. The race 1203constitutes a first race while the race 1202 constitutes a second race.A plurality of second balancing balls or weights 1210 are freely movablein groove 1202 and a first set of balancing balls or weights 1211 arelocked in the position shown in groove 1203 by a friction pad 1212mounted in groove 1203 and an axially movable collar 1213. Likewise, aplurality of control balls 1214 are intermittently positioned around thecircumference of groove 1204 between the outer face 1220 of balancingdevice 1200 and the inside wedge shaped surface of movable collar 1213.A flat spring 1221 connected to bolt 1222 maintains force on the collar1213 tending to bias the collar 1213 leftwardly as viewed in FIG. 23.

In operation, as the balancing device 1200 is initially rotated,balancing balls 1210 are free to move within groove 1202 and will reacha position tending to remove any imbalance then existing while theweights 1211 are fixed in position. At a predetermined angular velocity,however, the control balls 1214 will tend to move outwardly with a forcesufficient to move collar 1213 rightwardly against the force of flatspring 1221. As collar 1213 moves rightwardly, balls 1211 are releasedand, again, will quickly assume a configuration that tends to remove anyimbalance in the apparatus. When the rotational speed of the balancingdevice 1200 is decreased, the collar 1213 will trap or fix the balls1211 in position as shown in FIG. 23 which will be maintained until therotational speed of the apparatus is again sufficient to move thecontrol balls 1214 outwardly against the wedge shaped surface 1223 ofmovable collar 1213.

It is further contemplated in the embodiment of FIG. 23 that if it isdesired to maintain the balancing balls 1211 in race 1203 in the lockedposition under all rotational circumstances, bolt 1224 is simplytightened which will remove all axial movement in collar 1213 until theoperator desires otherwise and manually loosens bolt 1224.

Two representative configurations for the races are illustrated in FIG.24. The first race 1312 is round as illustrated. A plurality of weights1313 are positioned in the first race 1312. Fluid 1314 is also placedwithin the first race 1312.

The second race 1320 is of a square configuration with balls 1321positioned within the race 1320. Fluid 1322 is also placed within thesecond race 1320.

Other factors being equal, the shear forces exerted on the balls 1313will be higher than the shear forces exerted on the balls 1321 by thefluid 1322 in race 1320 because of the closer average distance betweenthe balls and the inner wall of the race. Thus, the movement of theballs 1321, 1313 could be staggered, for example, by placing fluidhaving the same viscosity in two races having different configurations.This would be intended to have the same affect as having fluids ofdifferent viscosities in races having the same configuration.

It will be understood that although the balls or weights in the racesare shown to be of different sizes and weights, the densities of thematerials may differ such that, for example, the balls or weights in onerace may be the same size as the balls or weights in a second racealthough the weights are different because of the two differentmaterials. Likewise, the weights may be of different sizes in therespective races but have the same weights, again because of thedensities of the materials used.

Likewise, it is envisioned that a member having at least three pathwayswith the same width, with all of the balls or weights being of equalsize, could be satisfactorily used in certain circumstances. Thepathways would conveniently be concentric and taking the same form, forexample, as the embodiment illustrated in FIG. 18 but with the threeinner races or pathways removed.

While it is presently anticipated that the counterbalancing apparatusaccording to the invention be made from a metallic material, it is alsocontemplated that other materials may well be appropriate such ascomposite material structures and plastics or the like, depending on theoperating conditions under which the counterbalancing apparatus isintended to function.

While specific embodiments of the invention have been described, suchembodiments should be considered as illustrative of the invention onlyand not as limiting its scope as defined in accordance with theaccompanying claims.

What is claimed:
 1. A method of removing imbalance through use of anapparatus that includes a first annular continuous race in which ispositioned at least one weight so that the weight is completely enclosedwithin the first annular race and a second annular race spaced from thefirst annular race and containing at least one second weight,comprising:initiating rotation of the apparatus about a rotational axis;fixing the at least one first weight in position within the firstannular race during initiation of rotation of the apparatus by urging amovable collar into contacting engagement with the at least one firstweight; allowing the at least one second weight in the second annularrace to freely move within the second annular race while the at leastone weight in the first annular race is fixed in position; continuingrotation of the apparatus about the rotational axis to increaserotational speed of the apparatus; moving the collar out of contactingengagement with the at least one first weight when the apparatus reachesa predetermined rotational speed so that the at least one first weightfreely moves within the first annular race and removes imbalance. 2.Method according to claim 1, including decreasing the rotational speedof the apparatus and fixing the at least one first weight in positionwithin the first annular race, the at least one first weight being fixedin position as the rotational speed of the apparatus is reduced byengaging the at least one first weight with the collar.
 3. Methodaccording to claim 1, wherein the step of fixing the at least one firstweight in position by urging the collar into contacting engagement withthe at least one first weight includes applying a biasing force of aspring to the collar to urge the collar towards the at least one firstweight.
 4. Method according to claim 1, including a control ballpositioned adjacent the collar, said step of fixing the at least onefirst weight including positioning the control ball so that the collarcontacts the at least one first weight, said step of moving the collarincludes moving the control ball so that the collar is axially displacedout of contacting engagement with the at least one first weight.